Verbal and non-verbal communicative acts mark the links within our discourse, help us to exchange turns and give backchannel in conversation. This book analyses the communicative system of gaze in depth, investigating its structure and functions the same way that words and gestures are studied, and shows how to do so by establishing a phonology, a morphology, and a semantics of eye communication, before finally outlining a lexicon of gaze. Poggi provides a detailed semantic analysis of lexical items, highlights the role of gaze in multimodal communication, and illustrates its uses in everyday life, politics, education, and musical performance. The meanings we communicate by gaze are intertwined with the multimodality of our communication, thus integrating, complementing, sometimes contradicting, whether deliberately or inadvertently, what we tell by words or gestures. Starting from a robust theoretical framework, this book also provides an overview of the methods that can be exploited to study gaze, ranging from ethnosemantics to observation and simulation, and provides examples of their use. A timely and original contribution that is essential reading for advanced students, scholars and researchers of multimodal communication, pragmatics, social psychology, and related areas.